Neural Tube Defects

2 Types of Neural Tube Defects

1. Spinal Bifida- an opening in the spine at birth that requires immediate surgery to close their spine and prevent further damage
   • a shunt is also needed to prevent hydrocephalus which is a spinal fluid build-up in the brain
   • infants may lack feeling in their legs and have later difficulties walking
   • as children, they also may have difficulty with bowel and bladder control
2. Anencephaly- complete or partial absence of the infant's brain at birth, causing extensive damage. Most of these babies are either stillborn or die soon after birth.
3. Encephalocele- a portion of brain is protruding out from the back area (occipital region) in a skin covered sac.
   • An encephalocele is a neural tube defect of lesser severity than anencephaly

Spinal Bifida

1. Lipomeningocele- a lipoma, or fatty tumor, which is covered by skin and located over the low back(lumbosacral spine)
   • Children often have nerve difficulties as they age, resulting in difficulty controlling their bowel and bladder, muscle strength and weakness, and pain
2. Meningocele- involves the coverings (or meninges) of the spinal cord as they are pushed out into a section of open backbone, to create a sack.
   • If there are nerves in this sac, the infant will experience paralysis
   • The sac must be closed or it will become very large, leak spinal fluid, and possibly lead to meningitis and death
3. Myelomeningocele- in which the meninges (coverings) and spinal nerves do not develop properly, resulting in spinal fluid leakage plus complete or partial paralysis of legs, bladder, and bowels

NDT Detection by Prenatal Testing

1. MSAFP - Maternal Serum Alpha Fetoprotein Test- a blood test of the woman at 14-16 weeks of pregnancy.
2. High Resolution Ultrasound- Can detect a NTD visually as early as 18 weeks of pregnancy.
3. Amniocentesis- A test of the amniotic fluid of the mother after at least 14 weeks of pregnancy

Facts:

• 1:35 chance of having an infant with NTDs if you have already had one child prior with NTDs
• 90% of babies born with neural tube defects are born into families where it has never happened before
• 75% of affected pregnancies end in miscarriage or still birth from NTDs, and only 25% of these infants are born alive
• Those at risk:
  1. Maternal insulin-dependent diabetes
  2. Use of anti-seizure medication
  3. Medical diagnosis of obesity
  4. Previous NDT-affected pregnancy
  5. Exposure to high temperature (hot tubs, fever, etc)
  6. More common among Caucasians with English or Irish ancestry

Causes: Both genetic and environmental factors